Toxoplasma chorioretinitis diagnosed by histopathology in a patient with AIDS.

Purpose: To demonstrate the diagnostic difficulties in cases of retinal necrosis in immunocompromised patients including the potential for false-negative anterior segment sampling and also to emphasize the utility of diagnostic vitrectomy with histopathologic examination.
Methods: This patient's chart was thoroughly reviewed to present salient features that are relevant to any ophthalmologist attempting to diagnose and treat chorioretinitis. A 38-year-old man with HIV/AIDS who presented with bilateral retinal necrosis. Thorough workup, including multiple samples of anterior chamber fluid for polymerase chain reaction, was negative.
Results: Diagnostic vitrectomy revealed a toxoplasma cyst. Triple therapy stabilized retinitis, although vision did not improve.
Conclusion: This case reminds the clinician to consider a broad differential diagnosis for retinal necrosis in immunocompromised hosts and, when serologic and anterior chamber samples are negative, to consider diagnostic vitrectomy for polymerase chain reaction and histopathologic examination.